1. Field of the Invention
The present invention relates to a method and apparatus for producing natural salt by treating sea water.
2. Description of Related Art
According to a currently known method of producing natural salt, a number of pieces of bamboo with branches are hung upside down in a tower formed by piling up blocks, sea water is sprinkled from thereabove and water is evaporated by wind and solar heat while flowing down on the surface of bamboo by which sea water is condensed and water is evaporated on evaporating shelves for three through seven days, thereafter, brine is moved to crystallizing shelves of a green house type and salt is crystallized. Successively, the brine is separated into salt and bittern. According to the salt production process, there is provided an advantage in which compared with a process of boiling it in a kettle, various rare substances are not changed in respect of the qualities or vanished by intense heat.
Meanwhile, as a process of producing drinking water artificially from sea water, there has been known a desalination apparatus by a reverse osmosis membrane process which is used in a district having a small amount of rainfall or a district having a small number of dams.
According to the salt producing process mentioned above, salt component is crystallized over a number of days and therefore, the efficiency is poor and the process is not suitable for mass production. As a result, expensive natural salt is brought about.
Further, according to the process of producing fresh water from sea water by the reverse osmosis membrane process, a very complicated and high degree of technology is required and the installation cost becomes high. Further, the efficiency is poor and the process is not suitable for mass production of fresh water.
It is the technological problem of the invention to realize a treating method and a treating apparatus of sea water capable of producing natural salt with no need of an expensive equipment, in an extremely short period of time and efficiently by paying attention to such problems.
The technical problem of the invention is revolved by the following means.
Invention according to a first through a seventh aspect relates to a method of treating sea water for producing salt by means of atomizing sea water by rotating a centrifugal generator and of evaporating a water component to crystallize the salt by blowing warm wind thereto, wherein between a treating chamber and an outflow portion for the evaporated water component there is arranged at least one of net and cloth in one stage or a plurality of stages, the salt component is adhered to at least one of the net and the cloth when the evaporated water component passes through at least one of the net and the cloth, and thereafter the adhered salt component is peeled and dropped from at least one of the net and cloth.
When the net and the cloth are respectively used in a plurality of stages, the respective nets and cloths may be directly overlapped or may be spaced with an interval being kept therebetween. Further, also when both the net and the cloth are used, they may be mutually overlapped or may be spaced. In this case, either may be laid above.
When sea water is atomized in this way, innumerable small particles of sea water are composed and therefore, the surface area in contrast to the volume becomes large and vaporization of the water component is facilitated. As a result, vaporization of the water component from the salt crystal can efficiently be carried out. Further, warm wind is blown thereto and therefore, vaporization of the water component is expedited by thermal energy and wind and natural salt can inexpensively be produced. Further, sea water is brought into very fine mist and therefore, natural salt having very fine particles can be provided. Distilled water can be recovered and utilized as fresh water. Accordingly, at least one or both of fresh water and salt can be produced.
Particularly, between the treating chamber and the outflow portion of the evaporating water component there is arranged at least one of net (first screen) and cloth (second screen) is arranged in one stage or a plurality of stages and accordingly, when the evaporated component passes through at least one of the net and the cloth, the salt component is prevented from passing therethrough and is adhered to at least one of the net and the cloth. Here, within the context of the present invention, the phrase of xe2x80x9cat least one of net and clothxe2x80x9d is used to mean either (1) net, (2) cloth, or (3) net and cloth. The cloth (second screen) has a mesh size smaller than that of the net (first screen).
As a result, it is possible to prevent the salt component separated from the water component and the condensed sea water from being discharged wastefully. Further, the salt component and the condensed sea water are hampered by at least one of the net and the cloth to suppress discharges therefrom. Therefore, an amount of the salt component contained in the discharged water component is reduced and accordingly, water obtained becomes more resembled to fresh water.
And, since the salt component adhered to the net and the cloth is peeled and dropped therefrom, only the salt component is efficiently recovered and mass-production of salt becomes possible.
According to the second aspect of the invention, there is provided a method of treating sea water according to the first aspect, wherein at least one of the net and the cloth is made to hang on a side portion of the treating chamber and the salt component is adhered thereto.
In this way, according to the method wherein at least one of the net and the cloth is made to hang also on a side portion of the treating chamber and the salt component is adhered thereto, also the salt component floating in the vicinity of a side wall of the treating chamber is adhered to the net and the cloth, so that salt is produced more efficiently by peeling and dropping the adhered salt component.
According to the third aspect, there is provided the method of treating sea water according to the first or second aspect, wherein a number of strings are made to hang on a lower side of at least one of the net and the cloth and the salt component is adhered to the number of strings. In this way, when a number of strings are made to hang below the net or the cloth for preventing the salt component from passing through without stopping and the salt component is adhered thereto, salt crystal can be provided before reaching the net or the cloth and by knocking or shaking the number of strings or knocking or shaking them after collecting them to one place, the salt component can easily be collected to one place.
According to the fourth aspect, there is provided the method of treating sea water according to the second aspect or the third aspect, wherein the salt component adhered to at least one of the net and the cloth is recovered by washing off the salt component by sea water or by other method. Further, in respect of a method of separating the salt component adhered onto at least one of the net and the cloth from the net or the cloth, there can be provided a method of knocking, shaking it down by applying vibration other than a method of washing it off by sea water.
In this way, when the salt component or the condensed sea water adhered to the net or the cloth by being prevented from passing therethrough can be recovered in the treating chamber when it is washed off or shaken off by spraying sea water and accordingly, the salt component separated from the water component or the condensed sea water can be utilized for salt production and salt production can be carried out efficiently.
According to the fifth aspect of the invention, there is provided a method of treating sea water according to any one of the first through the fourth aspects, wherein the atomization of the sea water is carried out by means of applying a centrifugal force to the sea water by rotating an impeller in which arcuate blades are radially provided in a space between two circular disks and which has a water injection port at its center.
In mass production of fresh water or natural salt, sea water needs to convert into small particles in a large amount such that small particles thereof as fine as possible are produced and according to a method of producing a mist by a centrifugal force produced by an impeller in which arcuate blades are radially provided in a space between two circular disks and which has a water injection port at its center as proposed by inventors of the invention in Japanese Patent Application No. 8-297129 and Japanese Patent Application No. 8-220618, a large amount of sea water can easily be finely atomized and a large amount of salt or fresh water can be produced.
According to the sixth aspect of the invention, there is provided a method of treating sea water in accordance with any one of the first through the fifth aspects, wherein sea water is atomized by scattering sea water in a treating chamber, warm wind is blown thereto, an evaporated water component is discharged to outside of the treating chamber and a crystallized salt component is stored in the treating chamber. In this way, by adopting the method of atomizing sea water and blowing warm wind thereto in a space of the treating chamber and discharging the evaporated water component to outside of the treating chamber, a large amount of fresh water and natural salt can be separated and therefore, mass production of natural salt or fresh water can easily be carried out. As a result, natural salt and fresh water can be supplied inexpensively.
According to the seventh aspect of the invention, there is provided the method of treating sea water according to any one of the first through the sixth aspects, wherein the sea water is atomized after preheating the sea water at a temperature to a degree by which components in the sea water are not altered. In this way, since the thermal energy is applied on sea water by preheating it when the sea water is made fine and scattered, vaporization of sea water and crystallization of natural salt are further expedited. In this case, sea water is heated at a temperature to a degree by which components in sea water are not altered and accordingly, quality of natural salt is not deteriorated.
Accordingly, when the fan 34 is rotated in a state in which the heat generating body 31 of, for example, a heater is operated, air sucked by the fan 34 is heated by the heat generating body 31, blown into the treating chamber 1 and also blown to the heating chamber 25. As a result, vaporization of fine particles of sea water in the treating chamber 1 is expedited and heating of air in the heating chamber 25 is expedited. Further, the heating achieves power particularly when the weather is deteriorated and solar energy cannot be expected.
An eighth aspect through a twenty-second aspect of the invention relate to an apparatus of treating sea water. According to the eighth aspect, there is provided an apparatus of treating sea water for producing salt by means of atomizing sea water by rotating a centrifugal generator and of evaporating a water component to crystallize the salt by blowing warm wind thereto wherein between a treating chamber and an outflow portion for the evaporated water component there is arranged at least one of net and cloth in one stage or a plurality of stages, and there is provided means for peeling and dropping the salt component adhered to at least one of the net and the cloth from at least one of the net and the cloth.
In this way, one stage or plural stages of at least one of the net and the cloth for preventing the salt component from escaping are arranged between the treating chamber and the outflow portion for the evaporated water component and accordingly, in producing salt by treating sea water, the salt component or the condensed sea water is hampered by the net or the cloth and the discharge is restrained and therefore, only the water component passes through the net or the cloth and is discharged.
And, there is provided means for peeling and dropping the salt component adhered to the net and the cloth and accordingly, the salt component and the condensed sea water can be separated more effectively from the water component to produce salt in mass-production basis, and the water component can be utilized as flesh water.
Different from the net, the cloth is not provided with gaps (meshes) and therefore, the salt component can effectively be prevented from passing therethrough without stopping, however, it is also effective to use the cloth along with the net. However, considerable effect is achieved even only with a net. In the case of installing plural stages of the net, when the respectives of net are constituted to directly overlap each other, the meshes are substantially made fine and the salt component or the condensed sea water can firmly be adhered thereto and recovered. Further, when they are installed at intervals, the salt component or the condensed sea water passes through the respectives of the net at plural times and the salt component or the condensed sea water can be adhered and recovered further effectively.
According to the ninth aspect of the invention, there is provided the apparatus of treating sea water according to the eighth aspect, wherein a number of strings are made to hang on a lower side of at least one of the net and the cloth for adhering the salt component. In this way, when a number of strings are made to hang below the net or the cloth for preventing the salt component from passing therethrough without stopping, before the salt component reaches the net or the cloth, the floating salt component is adhered to the large number of strings and accordingly, recovery of the salt component is facilitated which is suitable for mass production.
According to the tenth aspect of the invention, there is provided the apparatus of treating sea water according to the eighth aspect or the ninth aspect, wherein means for washing off the salt component by spraying the sea water at least on one of the net and the cloth is arranged on an upper side of at least one of the net and the cloth.
In this way, owing to the structure in which the salt component or the condensed sea water adhered to the net or the cloth is washed off by scattering sea water to the net or the cloth, the salt component or the condensed sea water adhered to the net or the cloth can be recovered and utilized in salt production. As a result, the salt component or the condensed sea water can be prevented from wastefully discharging and the yield of salt production is promoted.
According to the eleventh aspect of the invention, there is provided an apparatus of treating sea water comprising means for atomizing and scattering sea water into a treating chamber and warm wind blowing means for blowing warm wind to mist of the sprayed sea water, wherein a duct hole for exhausting vapor produced by being vaporized in a treating chamber to outside of the treating chamber is provided at a roof portion of the treating chamber. The roof portion of the treating chamber indicates a wall portion closing an upper portion of the treating chamber. The warm wind blowing means includes a structure in which the atomizing means serves also as the warm wind blowing means by supplying warm air to an intake side of the scattering means and means exclusive for blowing warm wind installed separately from the scattering means.
And, net is provided so as to cover the duct hole, and means for peeling and dropping the salt component adhered to the net is provided.
In this way, means for atomizing and scattering sea water in the treating chamber is provided and therefore, sea water can be atomized in the treating chamber and can be scattered into a wide space such that vaporization of the water component is facilitated. Further, the warm wind blowing means is provided and therefore, thermal energy and wind can be applied to small particles of sea water. Vaporized vapor rises since its specific weight is light and the duct hole for exhausting is opened at the roof portion of the treating chamber and accordingly, only the water component can smoothly be discharged from the treating chamber and can be separated from crystals of natural salt.
Further, the net is provided so as to cover the duct of the roof portion for discharging the water vapor vaporized in the treating chamber, and means for peeling and dropping the salt component adhered to the net is provided and accordingly, it is possible to peel and drop the salt component adhered to the net and the condensed sea water by such means as washing off with the sea water, so that it is suitable for efficiently producing salt in mass-production basis.
According to the twelfth aspect of the invention, there is provided the apparatus of treating sea water according to the eleventh aspect, wherein at least one stage of at least one of a net and a cloth for adhering a salt component is arranged at a midway or on a lower side of the duct hole and means for washing off a salt component by scattering the sea water to at least one of the net and the cloth is arranged on an upper side of at least one of the net and the cloth.
In this way, owing to the constitution in which the net or the cloth for adhering the salt component is arranged in a midway or on a lower side of the duct hole opened between inside of the treating chamber and outside of the treating chamber, the net or the cloth having a comparatively small area is sufficient and means for washing off the salt component or the condensed sea water adhered to the net or the cloth is sufficient with a small scale. Further, all the salt component or the condensed sea water discharged from inside of the treating chamber to outside thereof passes through the duct hole and accordingly, the salt component or the condensed sea water can efficiently be recovered.
According to the thirteenth aspect of the invention, there is provided the apparatus of treating sea water according to the eleventh or the twelfth aspect, wherein an outer roof is provided above a roof portion of the treating chamber and an outer wall is provided at outside of side walls of the treating chamber, wherein means for scattering the sea water is provided above the outer roof, and wherein a water distributing constitution in which the sea water recovered from above the outer, roof is supplied to the atomizing means is constituted. Sea water recovered from above the outer roof is not necessarily be supplied directly to the atomizing means. Accordingly, the aspect includes also a case in which sea water is supplied to the atomizing means via a preheating unit.
In this way, sea water is scattered on the outer roof, the water component is evaporated by solar ray and wind and concentration of the salt component is increased and thereafter, sea water is supplied to the atomizing means and fine mist of sea water is produced in the treating chamber and therefore, separation of the water component from the salt component can efficiently be carried out. Further, by scattering sea water on the upper roof and cooling a space between the outer roof and the roof of the treating chamber, vapor which has been vaporized in the treating chamber and flows in the space is cooled and condensed and accordingly, the space constitutes negative pressure. As a result, an effect of sucking smoothly vapor in the treating chamber into the space can also be achieved.
Further, when vapor is cooled and liquefied to constitute liquid, thermal energy absorbed in the treating chamber as vaporization heat is discharged as liquefaction heat. The discharged heat can expedite condensation by warming sea water scattered on the outer roof and can contribute to vaporization of small particles of sea water by being transferred also into the treating chamber.
According to the fourteenth aspect of the invention, there is provided the apparatus of treating sea water according to the eleventh, the twelfth or the thirteenth aspect, wherein at least one stage of at least one of the net and the cloth for adhering the salt component is arranged at least one of a lower side of the roof portion of the treating chamber (inner roof) and inner sides of the side walls.
In this way, owing to the constitution in which the net or the cloth for adhering the salt component is arranged on the lower side of the inner roof of the treating chamber or on the inner sides of the side walls, the net or the cloth can be stretched in a wide region and the salt component or the condensed sea water can be caught in a wide area and accordingly, the efficiency of recovering the salt component or the condensed sea water is increased.
According to the fifteenth aspect of the invention, there is provided the apparatus of treating sea water according to the fourteenth aspect, wherein a number of strings are made to hang from a lower side of at least one of the net and the cloth for adhering the salt component. In this way, in the inside of the treating chamber, owing to the constitution in which the number of strings are made to hang below the net or the cloth for preventing the salt component from passing therethrough without stopping, the salt component adheres to the number of strings before reaching the net or the cloth and accordingly, the salt component adhered to the strings can be shaken off and recovery of the salt component is facilitated which is suitable for mass production.
According to the sixteenth aspect of the invention, there is provided the apparatus of treating sea water according to the fourteenth or the fifteenth aspect, wherein means for washing off the salt component by scattering the sea water to at least one of the net and the cloth is arranged on an upper side of at least one of the net and the cloth on the lower side of the roof portion of the treating chamber. In this way, owing to the constitution in which sea water is scattered from the upper side of the net on the lower side of the inner roof to thereby wash off the salt component, a large amount of the salt component or the condensed sea water adhered to the net or the cloth in a wide region can efficiently be recovered and utilized in salt production.
According to the seventeenth aspect of the invention, there is provided the apparatus of treating sea water according to any one of the eleventh through the sixteenth aspects, further comprising a preheating unit for heating the sea water supplied to the means for atomizing the sea water at a temperature to a degree by which components in the sea water are not alterated.
In this way, before supplying sea water to the atomizing means, owing to the preheating unit of sea water, sea water accompanied by thermal energy is supplied to the atomizing means and therefore, vaporization of water component of mist of sea water is further expedited.
According to the eighteenth aspect of the invention, there is provided the apparatus of treating sea water according to any one of the eleventh through the seventeenth aspects, wherein a heating chamber is installed at a distance from the side wall of the treating chamber, wherein the sea water preheating means is installed in the heating chamber, and wherein heated air in the heating chamber is blown by blowing means from an opening opened at the side wall into the treating chamber. The blowing means includes exclusive blowing means and blowing means provided to the mist scattering device.
In this way, the heating chamber is installed at a distance from the side wall of the treating chamber and warm wind in the heating chamber is blown to inside of the treating chamber and accordingly, a large amount of thermal energy can be provided to fine mist of sea water in the treating chamber and vaporization of the water component is further expedited. Further, the preheating unit of sea water according to the seventeenth aspect is installed in the heating chamber and extra heat produced from the sea water preheating unit is utilized which is economical.
According to the nineteenth aspect of the invention, there is provided the apparatus of treating sea water according to any one of the eleventh through the eighteenth aspects, further comprising a heating facility for supplying warm air into the treating chamber. In this way, owing to the constitution capable of supplying warm air produced in the heating facility into the treating chamber, even when solar energy cannot be utilized as in, for example, rainy weather, thermal energy is provided to small particles of sea water in the treating chamber and the water component and the salt component can smoothly be separated from each other.
According to the twentieth aspect of the invention, there is provided the apparatus of treating sea water according to any one of the thirteenth through the nineteenth aspects, wherein a water distributing structure capable of supplying the sea water to the preheating unit without via the outer roof is constituted. When the processing of condensing sea water by natural energy on the outer roof cannot be carried out owing to rainy weather, the sea water is supplied as it is to the preheating unit, and can be supplied into the treating chamber after being provided with thermal energy and accordingly, natural salt and fresh water can be produced without being controlled by weather.
According to the twenty-first aspect of the invention, there is provided the apparatus of treating sea water according to any one of the thirteenth through the twentieth aspects, wherein a water distributing structure for scattering the sea water in a sea water tank for storing sea water by recovering the sea water scattered on the outer roof, guiding and scattering the sea water again onto the outer roof is constituted. In this way, owing to the structure in which sea water the salt component of which is condensed by scattering the sea water on the outer roof, is guided and scattered again on the outer roof, the sea water can be condensed by natural energy on the upper roof over a plurality of times. Therefore, it is suitable for the case of mass production of natural salt.
According to the twenty-second aspect of the invention, there is provided the apparatus of treating sea water according to any one of the thirteenth through the twenty-first aspects, wherein at least the roof of the treating chamber and the outer roof comprise transparent bodies. In this way, by constituting the outer roof and the roof of the treating chamber by transparent bodies, solar energy can reach the inside of the treating chamber to thereby heat it and accordingly, in fair weather, vaporization of fine mist of sea water in the treating chamber can efficiently be carried out.
In this way, according to salt or condensed sea water including salt provided by the invention, by removing bittern by reducing the water component, only crystals of salt can be separated.